The article is devoted to the results of the study of an old but not solved up to now problem in the Yakut ethnography concerning the origin of a big ethnical group Khoro which is one of the main units in the ethnical composition of the Yakuts living in the North of Siberia. The problem is urgent for its being unsolved does not make it possible to create an integral picture of the formation of the Yakut people. Most researchers think that the original motherland of the Khorolors (the plural of “Khoro”) was on the western side of the Baikal in Bargujin-Tokum1, where they were a part of a Buryat tribal community of the Khori living now in Transbaikalia. In 1207 during the conquest of Bargujin-Tokum by Chinggis-khan’s troops a part of the Khori tribe escaping from the Mongols fled to the Middle Lena and never came back to the Baikal. When identifying both the groups only the resemblance of the names Khoro and Khori was taken into account which could not provide an exact result. Meanwhile the Khorolors cults of the Raven and the Eagle and associated with them “raven” and “eagle” myths and the same, typologically similar myths about the totemic forefathers mentioned above among the Paleoasians of the North-East Asia and North-American Indians make it clear that the Khorolors of Yakutia are of paleoasian origin. The Khorolors belonged to the southern branch of the Paleoasians and they resided in the lower Amur where there was their motherland Khoro sire. In a number of early Chinese and Korean chronicles this locality is called Kori. It is just there that one can find the sources for the ethnogenesis of the Koreans in which the northern Paleoasian component took a noticeable part. Supposedly at the end of the I millennium A.D., the Khorolors from the Lower Amur migrated to the North and permanently settled in the land of Yakutia. This is an evidence of the fact that in the ethnogenesis of the Yakuts the Paleoasian ethnical layer played a considerable part in addition to the ancient Tiurk substratum.